PUSHKAR, INDIA – For the 15th year, Mavir Tofe is camping under the same tree at the world’s largest camel fair. “When I first came, the tree was like this,” he says, holding his hand next to his thigh. “Now,” he adds, raising his hand above his head, “the tree is like this.”

For decades, herders like Mr. Tofe have walked hundreds of miles to Pushkar, in the northwestern Indian state of Rajasthan, for the eight-day festival at the end of October with more than 20,000 camels and thousands more horses and cows. Men like Tofe are here to buy and sell livestock, but in recent years hundreds of hawkers and thousands of tourists have transformed the event into a chaotic carnival.

Above the sound of belching camels and whinnying horses, peddlers hawk their wares. “Fifteen years ago, nobody was selling things,” said one vendor from Uttar Pradesh Province, camel-bone necklaces hanging from his fingers.

In addition to tourists, the spectacle now attracts foreign veterinarians. In 2002, two nonprofit clinics based in Rajasthan began offering free care at the fair, treating hundreds of camels for mange, saddle sores, and nose-ring infections. “I could be at home worrying about people’s pet rabbits,” said Jack Reece, a British veterinary surgeon volunteering this year at the fair, “or I could be here. Is there a contest?”

For Indian herders, meanwhile, the decades-old purpose of the event remains. Tofe plans to buy 25 camels and then walk with them 350 miles back to his hometown in northwestern Rajasthan.